Imperfect perception: Sensory dysfunctions and relationalism

Sensory dysfunctions shape how many of us experience the world. Examples include vision loss and colour-blindness, but also less well-known dysfunctions like hyperacusis, where sounds are experienced as unbearably loud, and parosmia, where familiar things smell distorted and disgusting. These conditions produce distinctive perceptual experiences – dysfunctional experiences – which are sometimes extremely different from those of normal perceivers. Sensory science, medicine, and psychology are uncovering the causes, mechanisms, and impact of sensory dysfunctions. Philosophy can make a unique contribution to understanding this phenomenon of high social relevance by applying its conceptual tools to the resulting experiences.
Dysfunctional experiences, in turn, provide an opportunity for advancing philosophical theories of perception. They raise a new challenge for relationalist theories, on which perceptions are fundamentally relations of awareness to the external environment. Dysfunctional experiences seem to involve a perceptual relation to the environment; but how can they be relations to the environment, just like the experiences of normal perceivers, if they are so different in sensory and affective character? For instance, how can a parosmic subject to whom wine smells sewage-like and disgusting be in a perceptual relation to the same environment as a subject to whom wine smells berry-like and delightful? The IMPERCEPT project turns this challenge into an opportunity. The core idea is that many dysfunctional experiences fundamentally involve a perceptual connection to the environment, albeit an anomalous and altered one: they are imperfect perceptions. Relationalist theories, I hypothesise, are especially well-equipped to offer a positive account of this perceptual connection. Through a range of case studies involving different senses, I will develop a framework for understanding the perceptual, affective, and cognitive aspects of dysfunctional experiences.